This invention relates to a magnetic head slider whose bottom plane is supported to face the operation plane of a magnetic disc and on which a cooperating magnetic head is mounted, the bottom plane being provided with high pressure applying-planes facing the magnetic head between the planes and the magnetic head external air streams are introduced by the rotation of the magnetic disc to produce compressed air streams and thus defining a compressed air stream path causing the slider and magnetic head to be removed from the operation plane of the magnetic disc.
The conventional magnetic memory device is generally of the type which is constructed by stacking a plurality of magnetic discs around a rotary shaft rotated by a proper drive mechanism at a substantially equal distance (such assembly is referred to as "a disc stack"). Set near the disc stack is a carriage which is made movable in parallel with the rotary shaft as well as radially thereof. The outer end of each of the access arms extending outward form the carriage is fitted with a magnetic head. The drive of the carriage causes the magnetic head to the shifted to a desired track formed on the magnetic disc, thereby enabling the reading of data from said track or the writing of data therein. The above-mentioned magnetic disc type memory device which is widely accepted still has much room to be improved. Reference is now made to said drawbacks. The magnetic head is fixed to a slider elastically attached to the end of the access arm by means of a load spring and gimbals mechanism. The conventional slider is typically illustrated in FIG. 1. A magnetic head is fixed to a slider 10 (in FIG. 1, only the core 11 of the magnetic head is indicated). The bottom plane of the slider 10 is provided with three ridges 12, 13, 14 which extend in parallel lengthwise of the slider 10 and project downward substantially to the same extent. A long groove 15 is defined between the ridges 12 and 13. A long groove 16 is similarly defined between the ridges 13 and 14. The left end portion of the ridges 12, 13, 14 as viewed from FIG. 1 is respectively provided with an inclined plane 12a, 13a, 14a. The height of said inclined plane is progressively reduced toward the tip of the left end portion.
The slider 10 is held in such a position that the respective upper flat planes 12b, 13b, 14b of the ridges 12, 13, 14 are positioned in parallel with the operation plane of the co-operating magnetic disc, and that the upper flat planes 12b, 13b, 14b are very closely spaced from the operation plane of the magnetic disc in order to cause external air streams produced around the slider 10 by the rotation of the magnetic disc to forcefully strike the aforesaid inclined planes 12a, 13a, 14a from the left side of FIG. 1. PG,4
When the magnetic disc ceases to rotate, the slider 10 contacts the magnetic disc by the urging face of the load spring. When reaching a certain rotation speed, the magnetic disc is pushed by air streams striking against the inclined planes 12a, 13a, 14a and is brought to a floating state. As a result, external air streams removing from the operation plane of the magnetic disc flow through a narrow passage defined between the operation plane of the magnetic disc and the upper flat planes 12b, 13b, 14b of the ridges 12, 13, 14 and are drawn off to the right side of FIG. 1. At this time compressed air streams are produced in the narrow passage, causing the slider 10 to be removed substantially to a predetermined position agains the urging force of the load spring. Therefore, the narrow passage is hereinafter referred to as "a high pressure path". The long groove 15 defined between the ridges 12, 13 and the long groove 16 defined between the ridges 13, 14 allow for the substantially free flow of a certain portion of air streams running through a space defind between the slider 10 and the operation plane of the magnetic disc. Consequently said long grooves 15, 16 are effective to reduce the amount of compressed air streams conducted through the above-defined high pressure path, thereby properly controlling a floating face applied to the slider 10.
When the slider 10 having the aforementioned construction is used and the magnetic head is positioned near the center of the magnetic disc, then the magnetic disc is rotated at a low speed. Therefore, air streams coming into a space defined between the slider 10 and magnetic disc has a relatively low pressure, causing the slider 10 to float from the operation plane of the magnetic disc with a low force. Conversely when the magnetic head is drawn near the periphery of the magnetic disc, the slider 10 floats from the operation plane of the magnetic disc with a stronger force. In other words, the distance at which the slider 10 or the magnetic head is removed from the magnetic disc varies with the position occupied by the slider 10 radially of the magnetic disc. Consequently, when the distance is large, the conventional magnetic head slider has a drawback that the recording and reproduction property of a magnetic disc type memory device is reduced; and when the distance is small the drawback is such that the surface of the magnetic disc is required to be worked accurately to prevent contacting of the disc surface with the magnetic head.